Registration of media type image/svg+xml

Chris Lilley chris at
Thu Dec 8 05:12:25 CET 2005

Hello ietf-types,

The SVG WG requests feedback on its standards tree media type
registration for image/svg+xml:

M.1 Introduction

   This appendix registers a new MIME media type, "image/svg+xml" in
   conformance with RegMedia and W3CRegMedia.

M.2 Registration of Media Type image/svg+xml

   MIME media type name:

   MIME subtype name:

   Required parameters:

   Optional parameters:

          The encoding of an SVG document shall be determined by the
          XML encoding declaration. This has identical semantics to the
          application/xml media type in the case where the charset
          parameter is omitted, as specified in RFC3023 sections
          8.9, 8.10 and 8.11.

   Encoding considerations:
          Same as for application/xml. See RFC3023, section 3.2.

   Restrictions on usage:

   Security considerations:
          As with other XML types and as noted in RFC3023 section
          10, repeated expansion of maliciously constructed XML
          entities can be used to consume large amounts of memory,
          which may cause XML processors in constrained environments to

          SVG documents may be transmitted in compressed form using
          gzip compression. For systems which employ MIME-like
          mechanisms, such as HTTP, this is indicated by the
          Content-Transfer-Encoding header; for systems which do not,
          such as direct filesystem access, this is indicated by the
          filename extension and by the Macintosh File Type Codes. In
          addition, gzip compressed content is readily recognised by
          the initial byte sequence as described in RFC1952 section

          Several SVG elements may cause arbitrary URIs to be
          referenced. In this case, the security issues of RFC3986,
          section 7, should be considered.

          In common with HTML, SVG documents may reference external
          media such as images, audio, video, style sheets, and
          scripting languages. Scripting languages are executable
          content. In this case, the security considerations in the
          Media Type registrations for those formats shall apply.

          In addition, because of the extensibility features for SVG
          and of XML in general, it is possible that "image/svg+xml"
          may describe content that has security implications beyond
          those described here. However, if the processor follows only
          the normative semantics of this specification, this content
          will be outside the SVG namespace and shall be ignored. Only
          in the case where the processor recognizes and processes the
          additional content, or where further processing of that
          content is dispatched to other processors, would security
          issues potentially arise. And in that case, they would fall
          outside the domain of this registration document.

   Interoperability considerations:
          This specification describes processing semantics that
          dictate behavior that must be followed when dealing with,
          among other things, unrecognized elements and attributes,
          both in the SVG namespace and in other namespaces.

          Because SVG is extensible, conformant "image/svg+xml"
          processors must expect that content received is well-formed
          XML, but it cannot be guaranteed that the content is valid to
          a particular DTD or Schema or that the processor will
          recognize all of the elements and attributes in the document.

          SVG has a published Test Suite and associated implementation
          report showing which implementations passed which tests at
          the time of the report. This information is periodically
          updated as new tests are added or as implementations improve.

   Published specification:
          This media type registration is extracted from Appendix M of
          the SVG 1.2 Tiny specification.

   Additional information:

   Person & email address to contact for further information:
          Dean Jackson, Chris Lilley (member-svg-media-type at

   Intended usage:

   Author/Change controller:
          The SVG specification is a work product of the World Wide Web
          Consortium's SVG Working Group. The W3C has change control
          over these specifications.

 Chris Lilley                    mailto:chris at
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG

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